Europe's Alphasat satellite takes its place in the payload ''stack'' for next Ariane 5 mission

Construction of the payload “stack” for Arianespace’s upcoming Ariane 5 flight is now underway at the Spaceport in French Guiana, with the Alphasat satellite readied for its positioning as the mission’s upper passenger.

During activity in the launch site’s Final Assembly Building for Ariane 5, Alphasat was installed atop the SYLDA dispenser system, which allows two spacecraft to be deployed on the same mission.

Developed by Astrium, Alphasat is one of the most sophisticated commercial communications satellites ever built. It will have a launch mass of 6,650 kg., and is the result of a large-scale public-private partnership involving Inmarsat and the European Space Agency (ESA).

The satellite carries an advanced, new generation L-band geo-mobile communications relay system that will augment Inmarsat’s Broadband Global Area Network (BGAN) service, enabling increased-capacity communications across Europe, Asia, Africa and the Middle East. This spacecraft features eight new-generation digital signal processors and an 11-meter antenna reflector. It also is configured with four technology demonstration payloads for ESA.

Alphasat is the first flight model of Europe’s new Alphabus high capacity satellite platform, developed jointly by Astrium and Thales Alenia Space with the support of ESA and the French CNES national space agency. The goal is to address the communications satellite market’s upper range – as the Alphabus platform is capable of satellite launch masses up to 8,800 kg. and power ratings as high as 22 kW.

For Arianespace’s upcoming Ariane 5 launch – set for July 25 – Alphasat will be orbited along with India’s INSAT-3D satellite, which has a mass at liftoff of approximately 2,100 kg. Built by the country’s Indian Space Research Organisation (ISRO) space agency, along with its ISRO Space Applications Centre – INSAT-3D is designed to provide enhanced meteorological observation and the monitoring of land/ocean surfaces. Also carried is a data relay transponder, along with a system to assist in satellite-aided search and rescue operations.

INSAT-3D will be riding as the Ariane 5 mission’s lower payload, located under Alphasat inside the SYLDA dispenser system.

The July 25 mission is designated Flight VA124 in Arianespace’s launcher family numbering system, signifying the 214th launch of an Ariane-series vehicle.